Most existing wheelchairs have two parallel, rearwardly-directed handles which are (a) separated by a distance equal to the width of the wheelchair (18 to 24 inches), and (b) parallel to the ground. This paired-handle design requires use of two hands for control of the wheelchair, making it difficult for a person to push a wheelchair with only one free hand. This is not a minor problem within a hospital environment, as sometimes medical or other equipment must be moved along with the wheelchair. Either two persons must then be used to move a single person in a wheelchair, or one person must push the wheelchair with one hand, and manipulate the equipment with the other, which is awkward and at times unsafe. Outside of the hospital environment, one may be in a situation where one must push a wheelchair-bound person with one hand, while carrying an umbrella or holding a parcel with the other.
Additionally, manual manipulation of a wheelchair using the standard, rearwardly-directed handles is ergonomically unsound or inefficient. The person pushing the wheelchair is forced to (a) grip the handle tightly with the hand, (b) orient and lock the wrist in an ulnar-deviated position, and (c) orient the forearm in a supinated position. These positions are uncomfortable, tiring, and drain strength.
There is a great need for wheelchair handlebars that allow a person pushing the wheelchair to do so in an ergonomically correct manner, grasping the handlebar loosely with either hand, or with both hands, without any uncomfortable twisting and/or bending of the forearms and wrists. To date, no completely satisfactory design has been proposed.
A number of wheelchair handlebars have been developed, such as those shown in U.S. Pat. Nos. 5,290,055 and 5,044,650 (see FIG. 1a).
These usually connect the handles with a straight bar that does relieve the strain on the hands and forearms, but do little to relieve the strain caused by ulnar deviated positioning of the wrists. Another handlebar design found in U.S. Pat. No. 4,872,697 (see FIG. 1b) is designed to allow a person to push a wheelchair with one hand. The parallel handles are connected with a crosspiece, and a single handgrip, or grip station, projects horizontally from the crosspiece. The grip station is substantially parallel to the handles, and provides no significant ergonomic advantage over the original handles.
Also, these handlebars are usually fitted to the existing handles by means of screw clamps or other forms of clamps. These clamps have the drawback that, if the clamps are not securely tightened or if they are accidentally loosened, the handlebar may come loose from the handles. These clamps often consist of multiple parts and project significantly out of the plane of the handles. They can also be time consuming to use. In a few cases, the crosspiece of the handlebar cannot be comfortably gripped due to the clamping mechanism. As previously stated, the grip station in the handlebar of FIG. 1a is ergonomically very poor. Unfortunately, the crosspiece to which the grip station is secured cannot be comfortably gripped by a user either due to the bulky and complicated clamping mechanism.